Preparation
1. **Prepare the Cake Batter:**
– Preheat your oven to 350°F (175°C).
– Grease and line a square baking pan with parchment paper.
– In a mixing bowl, cream together the softened butter and sugar until light and fluffy.
– Add the eggs one at a time, beating well after each addition.
– Mix in the vanilla extract.
– In a separate bowl, whisk together the flour, baking powder, and salt.
– Gradually add the dry ingredients to the butter mixture, alternating with the milk, beginning and ending with the dry ingredients. Mix until just combined.
2. **Prepare the Cream Filling:**
– In a saucepan, heat the milk over medium heat until it begins to steam (do not boil).
– In a bowl, whisk together the sugar, cornstarch, and egg yolks until smooth.
– Slowly pour the hot milk into the egg mixture, whisking constantly.
– Return the mixture to the saucepan and cook over medium heat, stirring constantly, until it thickens and begins to boil.
– Remove from heat and stir in the vanilla extract (and almond paste, if using).
– Allow the cream filling to cool slightly.
3. **Assemble the Cake:**
– Pour half of the cake batter into the prepared baking pan.
– Spoon the cream filling over the batter, spreading it evenly.
– Top with the remaining cake batter, spreading it to cover the filling.
– Sprinkle the sliced almonds evenly over the top of the batter.
4. **Bake the Cake:**
– Bake in the preheated oven for 35-40 minutes, or until a toothpick inserted into the center comes out clean.
– Allow the cake to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.
5. **Serve:**
